Chapter 14 Flashcards
(34 cards)
Hydrocarbons are most effectively put out using what type of foam?
Class b
Polar solvents fuels are best extinguished using what type of foam?
Special alcohol resistant formulations of firefighting foam
Foam is proportioned in what 4 basic methods?
Induction, injection, batch mixing, and premixing
Batch mixing is most commonly used with what type of foam?
Class A foam
When batch mixing class B foam concentrates what must be done?
Tank water must be circulated to ensure proper mixing before discharge
What should be throughly flushed after using foams?
Fire pump associated piping, as well as tanks, hose, and appliances
Premix systems are limited to one time use applications. Once used they must be?
Completely emptied, flushed, and refilled before they can be used again
How is foam stored?
Pails, barrels, totes, and apparatus tanks
Mixing different types or brands of foam concentrate should be?
Avoided as the result may prove ineffective for application and have reduced suppression capabilities
The shelf life of properly stored foam can be as long as?
20 years
What percent foam concentration should be used for the following?
Fire attack and overhaul with standard fog nozzle 0.2-0.5
Exposure protection with standard fog nozzle 0.5-1.0
Any application with air aspirating nozzles 0.3-0.7
Any application with compressed air foam system 0.2-0.5
Class b foam has a shelf life of ?
10 years for protein based, 20-25 for synthetic
What are the 3 foam expansion categories?
Low- 20:1
Medium 20:1-200:1
High 200:1- 1000:1
Once you bring foam application you should?
Continue without interruption from an uphill and upwind position until extinguishment is complete
What are the three common types of portable foam proportioners?
In-line foam eductors, foam nozzle eductors, and self educting master streams
What should be done to properly maintain foam eductors after each use?
Use a bucket of water to immerse the foam pickup tube, letting it induct for at least one minute
The foam eductor inlet should be no more than how many feet above the liquid surface of the foam concentrate?
No more than 6 feet above the liquid surface of the foam concentrate
What will happen if the nozzle and eductor don’t have the same gpm rating?
If the nozzle flows at a higher rate, too much concentrate will be used depleting resources and creating a foam blanket that is “richer” than necessary. If the nozzle flows at a lower rate not enough concentrate will be used resulting in poor quality foam
What is a major advantage of the self educting nozzle?
The pressure drop is much lower (10 percent or less) than most standard foam nozzle eductors
When using a JRC (jet ratio controller) foam concentrate can be located as far as how many feet from the self educting master stream nozzle, and up to how much feet of elevation change?
As far as 3000 ft away from the self educting master stream nozzle, and up to 50 ft of elevation change
Installed in line eductors are most commonly used to proportion what type of foam?
Class B, installed in line eductors are usually not effective for the very low concentrations used in class A foam operations
What is good to know about your apparatus if it has an around the pump proportioner?
If it can only be operated when the apparatus is operating from the onboard water tank, because inlet water pressure greater than 10 psi will not allow foam concentrate to enter the pump intake in some older models.
True or false. Can around the pump proportioners flow both foam and plain water from the pump at the same time?
False, it cannot flow both at the same time
What is one of the most common types of foam proportioning systems?
Bypass-type balanced pressure proportioners
